The transactions are indeed confirmed. According to block explorer there are (lets say) 20BTC as a final balance. However when i am sweeping on electrum its saying the sweep amount is 10BTC.
So what do you mean by unconfirmed? The last transaction on the wallet is possibly from months ago.
You'll know if a transaction is unconfirmed if you lookup the address on block explorers. It'll simply say unconfirmed transaction or something similar (look at
this, for example. It says "Unconfirmed Transaction! in red.).
If all of your transactions are already confirmed and importing makes your wallet hangs and you're already using the latest version I can only guess that electrum is unable to understand some of the transactions. We can't really help you in this case unless you can give us the address (either by PM or post here) so we can look at the transactions.